The purpose of this research is to investigate the molecular and genetic basis of aging. Our goals are to transform fibroblasts from cell lines of interest and to determine mutagenesis in these cell lines, using several different approaches to measuring mutagenesis. Cell lines which we will use are derived from patients with inherited diseases which are thought to represent accelerated aging or which represent defects in DNA repair. We will transform and immortalize fibroblasts isolated from patints with progeria, Werner syndrome, xeroderma pigmentosum, and Cockayne syndrome. Availability of transformed, immortalized fibroblast cell lines will enable us to carry cultures for an extended period of time with an improved growth rate relative to primary cells and will form a stable basis for the mutagenesis studies. To study mutagenesis in these cell lines we will measure the rate of mutation using the selectable HPRT marker in the cellular genome, mutagenesis of dominant selectable markers encoded on shuttle vectors, and mutagenesis of single copy of genes inserted in the cellular genome using retroviral shuttle vectors. The results of these studies will allow us to determine whether or not cells from patients with aging diseases show an alteration in mutagenesis relative to normal cell lines and relative to the cell lines representing DNA repair defects, already suggested to show increased mutagenesis. These results will inform us of whether cell lines from these diseases show changes in mutagenesis which may be related to the basic molecular biology of aging and will be an important basis concerning the models of the aging process.